Batrisiella bomea, Yin, 2022

Yin, Zi-Wei, 2022, The Batrisini of Tibet: unveiling an enigmatic ant-loving beetle diversity at Earth’s “ Third Pole ” (Coleoptera, Staphylinidae, Pselaphinae), Zootaxa 5111 (1), pp. 1-211 : 76-77

Batrisiella bomea sp. nov.

( Figs 32 , 80B , 97A, B, D )

Chinese common name: 波ṁ小毛唇à甲

Type material (64 exx.). HOLOTYPE: CHINA: ♂ , ‘ China: Xizang, Nyingchi City, pass nr. Yigong Tea Farm , 30°10’14”N, 94°55’51”E, 2200–2400 m, 11.vii.2021, Peng, Yin & Zhang, Ʊ Ẫffż 波ṁ县ƌŭē厂 ’ ( SNUC) . PARATYPES: CHINA: 5 ♂♂, 3 ♀♀, same data as that of holotype; 23 ♂♂, 32 ♀♀ , China: Xizang, Nyingchi City, Tongmai Town, pass nr. 102 Tunnel , 30°04’15”N, 95°08’07”E, 2150-2400 m, 12.vii.2021, Peng, Yin & Zhang, Ʊ Ẫȃ 9 102 Ṁdz (all paratypes in SNUC) .

Diagnosis. Male. Body length approximately 1.7–1.8 mm. Head subtruncate at base; vertexal foveae moderately large and asetose, with transverse sulcus between antennal tubercles; antenna moderately elongate; antennomeres each slightly elongate, 9–11 enlarged to form moderately distinct club, with modified antennomeres 8–10. Discal stria of elytron extending to approximately apical 1/5 of elytral length. Legs simple. Aedeagus strongly asymmetric; median lobe with large basal capsule, basoventral projection short, ventral stalk narrowing towards apex; dorsal lobe strongly curved, with broad, rounded apex; parameres reduced to single membranous structure. Female. Body length approximately 1.7–1.8 mm; antenna shorter, antennae lacking modifications, genitalia as in Fig. 32G .

Description. Male. Body ( Fig. 32A ) length 1.69–1.78 mm; color reddish-brown, tarsi and mouthparts lighter. Dorsal surface of body covered with short pubescence.

Head ( Fig. 32B ) subtruncate at base, slightly broader than long, length 0.36–0.38 mm, width across eyes 0.40– 0.43 mm; vertex finely punctate, with moderately large, asetose vertexal foveae (dorsal tentorial pits), lacking median carina, with transverse, sinuate sulcus between antennal tubercles; frons coarsely punctate, weakly impressed medially, anteriorly confluent with clypeus; clypeus smooth, anterior margin carinate and moderately raised; ocularmandibular ridge (with upper and lower carinae) broad. Venter with tiny gular foveae (posterior tentorial pits) originating from shared small pit, with thin median carina extending from foveae anteriorly to mouthparts. Compound eyes prominent, composed of approximately 23 ommatidia. Antenna moderately short, length 0.85–0.90 mm, apical three antennomeres forming moderately distinct club, with modified antennomeres 8–10 ( Fig. 32C ); antennomere 1 thick, subcylindrical, laterally with internal glandular structure, 2–7 each slightly elongate, 8 broader than 7, 9 much larger than 8, 8 and 9 each with short, thickened setae, 10 larger than 9, constricted at base and dilated at apex, 11 longest, sub-fusiform.

Pronotum ( Fig. 32B ) approximately as long as broad, length 0.40–0.41 mm, width 0.42–0.43 mm, widest at middle; lateral margins rounded; disc slightly convex, finely punctate, pubescent, median longitudinal sulcus broad, as long as semicircular lateral sulci in dorsal view, the latter extending from dorsal surface laterally and posteriorly and then fusing with lateral ends of antebasal sulcus; lacking median antebasal fovea, lateral antebasal foveae connected by transverse antebasal sulcus; outer and inner pair of basolateral foveae distinct. Prosternum with anterior part slightly longer than coxal part, with distinct lateral procoxal foveae; hypomeral ridge extending from base to middle of anterior part, with round lateral antebasal hypomeral impression; margin of coxal cavity weakly carinate.

Elytra much wider than long, length 0.53–0.57 mm, width 0.68–0.74 mm; each elytron with two large, asetose basal foveae, lacking subbasal fovea; discal stria extending from outer basal fovea to slightly more than apical 1/5 of elytral length; humerus angulate, small subhumeral fovea present, with carinate marginal stria extending posteriorly from fovea to elytral posterior margin and anteriorly to dorsal surface of elytron.

Mesoventrite short, demarcated from metaventrite by ridged anterior edges of impressed areas where lateral mesocoxal foveae situated at mesal margins, with pair of thin admesal carinae; setose median mesoventral foveae widely separated, lateral mesoventral foveae large and setose, broadly forked internally; intercoxal process short. Metaventrite moderately projecting admesally, inclined toward middle, with large, setose lateral mesocoxal foveae and pair of smaller, setose lateral metaventral foveae, posterior margin broadly and weakly emarginate at middle, lacking split.

Legs simple, lacking spines or tubercles.

Abdomen widest at lateral margins of tergite 1 (IV), length 0.46–0.51 mm, width 0.62–0.67 mm. Tergite 1 (IV) longer than tergites 2–4 (V–VII) combined in dorsal view, setose basal sulcus separated by two mediobasal and one pair of basolateral foveae, with pair of long discal carinae, marginal carina present only at basal third; tergites 2–4 (V–VII) tightly compressed, 2–3 lacking and 4 with one pair of basolateral foveae, tergite 4 shorter than 2 and 3 combined along middle, tergite 5 (VIII) semicircular, posterior margin roundly and shallowly emarginate at middle. Sternite 2 (IV) with large mediobasal and pair of broad, setose basolateral sockets, with long lateral carinae, midlength slightly longer than 3–4 (V–VI) combined, sternites 3–5 (V–VII) lacking foveae, sternite 6 (VIII) with posterior margin slightly emarginate, sternite 7 (IX) ( Fig. 32D ) slightly oval, weakly sclerotized at apical part and with few long setae along apical margin.

Aedeagus ( Fig. 32E–F ) 0.23 mm long, strongly asymmetric; median lobe with large basal capsule and subtriangular foramen, basoventral projection short, ventral stalk elongate and protruding, curved, narrowing toward apex; dorsal lobe elongate, recumbent, strongly curved and C-shaped in anterior view, in lateral view apically broadened and with rounded apex; parameres reduced to single membranous structure.

Female. Similar to male in external morphology; antenna shorter; each compound eye composed of approximately 18 ommatidia; humerus weakly angulate; legs simple. Measurements (as for male): body length 1.71–1.81 mm; length/width of head 0.36–0.38/ 0.41–0.42 mm, pronotum 0.40/ 0.41–0.42 mm, elytra 0.52–0.53/ 0.69–0.70 mm; abdomen 0.56–0.57/ 0.66 mm; length of antenna 0.84–0.86 mm; maximum width of genitalia ( Fig. 32G ) 0.25 mm.

Comparative notes. The new species can be readily separated from all congeners in Tibet and northern India by the location of the male sexual characters on the antennal clubs and their unique forms, as well as by the characteristic form of the aedeagus.

Distribution. Bomê County, Tibet, SW China ( Figs 80B , 97A, B, D ).

Etymology. The new species is named after Bomê County, where the type locality is located.

Figures

FIGURE 32. Morphology of Batrisiella bomea sp. nov. (A–F. Male. G. Female). A. Dorsal habitus. B. Head and pronotum. C. Antennomeres 8–11. D. Sternite 7 (IX). E, F. Aedeagus, anterior (E) and lateral (F). G. Genitalia. Scale bars: 0.5 mm in A; 0.3 mm in B; 0.2 mm in C, E, F; 0.1 mm in D, G.

FIGURE 80. Distribution of Tibetan Batrisini. A. Batriscenaulax campestris sp. nov. B. Batrisiella acclivis sp. nov. (circle), B. beibeng sp. nov. (triangle), B. bomea sp. nov. (square) and B. concisa sp. nov. (cross). C. B. curvitibialis sp. nov. (circle), B. ganma sp. nov. (triangle), B. guttata sp. nov. (square) and B. zhujianqingi (diamond).

FIGURE 97. Environment of and collecting sites at Nyingchi area. A. Sign of Yigong Tea Farm (ƌŭē厂). B. Forest near Yigong. C. Forest at Pailong Township (ḦË乡). D. Forest near Tongmai Town (ȃ9W).